01 - Whisk buttermilk with salt, garlic powder, onion powder, cayenne pepper, and black pepper in a large bowl until thoroughly combined.
02 - Submerge chicken pieces in the marinade, ensuring complete coverage. Cover bowl and refrigerate for at least 2 hours, preferably overnight for maximum flavor penetration.
03 - Combine flour, paprika, salt, black pepper, cayenne pepper, and baking powder in a separate bowl. Mix well to distribute spices evenly throughout the flour.
04 - Remove chicken from marinade, allowing excess liquid to drip off. Press each piece firmly into the flour mixture, turning to coat all surfaces thoroughly. Transfer coated pieces to a wire rack and let rest for 10 minutes to set the coating.
05 - Pour vegetable oil into a deep fryer or heavy-bottomed pot. Heat to 350°F, maintaining temperature throughout the frying process.
06 - Carefully lower chicken pieces into hot oil in small batches, avoiding overcrowding. Fry for 12 to 15 minutes, turning occasionally, until golden brown and crisp with an internal temperature of 165°F.
07 - Transfer fried chicken to a wire rack or paper towels to drain excess oil. Let rest for 5 minutes before serving to allow juices to redistribute.